# Campus VoIP

> Markdown source of <https://docs.calebsargeant.com/networking/cisco/switching/campus-voip/>.

## Why an Organization Would use IPT

Trackable Cost Savings:

- Moves, Adds, and changes (Macs)
- Bandwidth and equipment efficiency
- Lower cost of voice transmission
- New applications and devices

## Phase One IP Telephony Migration

- Keep the PBX system and digital phones
- Calls routed over WAN rather than PSTN
  - Major benefit: Free LD
  - Major requirement: QoS

## Phase Two IP Telephony Migration

- Voice and Data network have become one
- PBX and Digital phones for sale on E-Bay
- True integration between voice and data
- Typically new structures start here

## Campus Issues to Power when Deploying VOIP

- Inline Power
- Dual VLANs
- QoS

## Understanding and Configuring Dual VLANs

``` text
switchport mode access
switchport access vlan 200
switchport voice vlan 100
```

## Understanding and Configuring QoS

- Two QoS markings:
  - Class of service (CoS): layer 2
  - Type of service (ToS): layer 3

``` text
mls qos trust cos
mls qos trust device cisco-phone
auto qos voip trust
no auto qos voip cisco-phone
```